Codling moth monitoring trap. Photo: Greg Krawczyk, Penn State
First generation codling moth still needs to be controlled
The first generation codling moth (CM) adults are still flying in high numbers in some Pennsylvania orchards. Although it is already more than 550 DD50 past the CM biofix, which normally would be the last timing for the application of insecticides against codling moth, male moths are still being collected in high numbers in pheromone traps.
This year CM flight appears to be again greatly extended past the traditional timing for the CM first generation. Please use the direct on-site observations (e.g., pheromone traps) to decide if additional insecticide applications are needed for the control of this CM generation. If male moths can find traps baited with synthetic CM sex pheromone, it strongly suggests the mating is still occurring, and eggs are still being deposited. Please see the comparison of CM first generation flights during last few seasons at the FREC orchards (Figure 1.).
Insecticides such as Altacor®, Besiege ®, Delegate®, Exirel®, Minecto Pro®, or Voliam Flexi® should provide excellent control of remaining first-generation codling moth larvae. Please remember that Altacor, Besiege, Exirel, Minecto and Voliam main ingredients share the same mode of action (IRAC Group 28, ryanodine receptors modulators, diamides) and should not be used for the control of consecutive generations of the pest. In addition to those products, the organically approved codling moth granulosis virus CpGv (in products such as Cyd-X®, Cyd-X HP® or Madex XP®) should also provide good control of CM neonate larvae. The products containing CpGv have short residual activity, and applications need to be repeated every seven days.
Figure 1. Codling moth flight seasonality during the 2013-2018 seasons. The moth capture data were collected from the same experimental apple orchard located at FREC in Biglerville, PA. 2018.
Tufted Apple Bud Moth (TABM) and Obliquebanded Leafroller (OBLR)
The adults of the first generation tufted apple bud moth (TABM), and obliquebanded leafroller (OBLR) also continue their flights in most Pennsylvania orchards. The SkyBit egg hatch developmental model forecasts about 25 (TABM) and 10 (OBLR) percent egg hatch for those two leafroller species on June 15.
While TABM larvae tend to feed on older leaves (Photo 1A), the preferred feeding sites for OBLR larvae are usually located at the top of the growing new shoots. If OBLR is the dominant leafroller species in the orchard, then applications of insecticides may need to be repeated to protect developing new foliage (Photo 1B). The most effective insecticides against leafrollers include the diamide products (the same as for codling moth), Delegate and Intrepid. For organic orchards, the best options to manage leafrollers include products containing Bacillus thuringiensis (such as Dipel® or Javelin ®) or Entrust(R) (IRAC Group 5).
Photo 1A. Tufted apple bud moth larvae are feeding on foliage. Photo: Greg Krawczyk, Penn State
Photo 1B. New growth on apple tree injured by obliquebanded leafroller larvae. Photo: Greg Krawczyk, Penn State
Oriental Fruit Moth (OFM)
The flight of the second generation Oriental fruit moth (OFM) is about to start this week and if trap data indicates the necessity for a special treatment (threshold of 10 plus moths per trap per week), the week of June 17 will be a good time to control OFM (about 10 percent egg hatch forecasted on June 20). Most diamide products mentioned in the CM and leafroller’s sections should also provide good control of OFM larvae. In peach and apple orchards, the presence of OFM population can also be relatively easy assessed by visual scouting for the presence or absence of wilted tops of terminals (Photos 2A, 2B, 2C).
Photo 2A. Injury caused by Oriental fruit moth larvae feeding inside young peach. Photo: Greg Krawczyk, Penn State
Photo 2B. Oriental fruit moth larvae in apple terminal shoots. Photo: Greg Krawczyk, Penn State
Photo 2C. Oriental fruit moth larvae feeding in young apple fruit (frass near the calyx end of the fruit.) Photo: Greg Krawczyk, Penn State
Leafhoppers and Spirea Aphids
It is also a good time to scout for the presence of leafhoppers, especially white apple leafhopper (WALH), potato leafhoppers (PLH) and rose leafhopper (RLH). All three species are somehow similar in appearance however the RLH nymphs can be distinguished by the presence of small black spots on the thorax and wing pads. Leafhopper adults and nymphs feed on the foliage of fruit trees with PLH being also a known as a vector able to spread fire blight. Special attention needs to be directed toward protecting newly planted orchards. Neonicotinoid insecticides such as Assail®, Belay®, Actara ® or products containing imidacloprid such as Admire Pro ® should provide excellent control of these pests as well as new colonies of the spirea aphids usually found on peach and apple leaves located near the top of the terminals.
Photo 3A. Leafhopper nymphs on an apple leaf. Photo: Greg Krawczyk, Penn State
Photo 3B. Spirea aphids on an apple leaf. Photo: Greg Krawczyk, Penn State
Woolly Apple Aphids (WAA), San Jose Scales (SJS), and European Red Mites
The month of June is a good time to start (or continue) extensive monitoring for woolly apple aphids (WAA), San Jose scales (SJS) and European red mites. The presence of white cottony fibers most likely found around leaf axils on sprouts or any wounds on wood suggests the necessity of insecticide application to control WAA (Photo 4). Diazinon® or Movento® are the best choices for controlling woolly apple aphids if the control provided by natural enemies is not effective. Both products plus Centaur ® and Esteem ® will also help if San Jose scale crawlers are detected on the fruit or young shoots on the tree (Photos 5A, 5B).
So far, this 2018 season’s atmospheric conditions were not too favorable for the development of European red mites. However, the incoming hot and dry weather may still cause a significant increase in the mite populations, especially if beneficial organisms such as predatory mites and Stethorus beetles are not present in the system. During the hot and dry summer days, the European red mites may complete a generation in less than two weeks.
Photo 4. Woolly apple aphid colonies on young apple branch. Photos: Greg Krawczyk, Penn State
Photo 5A. San Jose scale males on the pheromone trap sticky floor (small goldish dots) Photo: Greg Krawczyk, Penn State
Photo 5B. Scale injuries on the bark of the apple tree. Photo: Greg Krawczyk, Penn State
Brown Marmorated Stink Bug (BMSB)
During last few weeks we continue to find low numbers of brown marmorated stink bug (BMSB) in areas around commercial peach and apple orchards. While in a majority of orchards no special treatment against BMSB should be necessary, the detection of juvenile BMSB stages (nymphs) usually warrants a specific insecticide application targeting BMSB, especially in stone fruit orchards. Various trap and lures are available for monitoring the presence of BMSB in and around orchards. BMSB traps and lures such as Stink Bug Xtra Combo (from Ag-Bio,Inc.), Stink Bug Rescue lure (Sterling International, Inc.) and Stink Bug Dual lure (from Trece Inc.) should provide solid information on potential movement of BMSB adults into orchards and are very effective tools to detect the already existing presence of BMSB adults and nymphs.
For the most effective and accurate detection of migrating stink bugs, the BMSB traps should be placed on the edges of orchards bordering woods or other possible sources of BMSB. The list of effective insecticides against BMSB includes most pyrethroids, neonicotinoids, and Lannate®.
Photo 6. Left to right: Brown marmorated stink bug pyramid style trap (AgBio, Inc.) clear sticky trap (Trece, Inc.) and Rescue trap (Sterling International, Inc.) deployed in the orchard and at the edge of the woods. Photos: Greg Krawczyk, Penn State
To view the insect hatch and trapping data for all major insect pests, please visit the Penn State Fruit Research and Extension Center (FREC) website. For pest management recommendations, refer to the Insect and Mite Control Toolbox.
To see the pest management methods described in this article and other exciting orchard research in action, join us for the Centennial Celebration of the Penn State Fruit Research and Extension Center!